The medical community and design community journals contain many papers discussing noise levels in neonatal intensive care units (NICU’s), how loud they should be and how to achieve those levels. Unfortunately, the recommended noise levels vary and the design recommendations contain few specifics that have been evaluated by qualified acoustical design professionals. Here is a sample of some of the recommended criteria.
- World Health Organization (WHO): daytime and nighttime Leq 30 dBA, nighttime Lmax 40 dBA
- AIA Interim Sound and Vibration Design Guidelines for Hospitals and Healthcare Facilities: Leq 30-40 dBA, applies only to heating, ventilation, and air-conditioning (HVAC) noise
- American Society of Heating Refrigeration and Air-Conditioning Engineers (ASHRAE): RC(N) 30-40, applies only to HVAC noise
- Report of the Sixth Census Conference on Newborn ICU Design, Orlando, FL (Jan. 25-27, 2006): Leq 45 dBA, L10 50 dBA, Lmax 65 dBA
- American Academy of Pediatrics Committee on Environmental Health (1997): DNL 45 dB
- Graven (2000): Leq 50 dBA, L10 55 dBA, Lmax 70 dBA
More unfortunate than the disparity among the criteria is that researchers have found that noise levels in most NICU’s exceed all of them. In order to significantly lower noise levels, it is necessary to seriously consider acoustics during the design of a NICU; this involves far more than selecting an acoustical ceiling tile. However, design is not the only driver of noise levels. It is also necessary to assess operations and where feasible modify them reduce the level of noise that is produced. Assisting design teams and hospitals in controlling noise levels is a large portion of the work that we perform at Acoustics By Design, and we are always striving to increase the depth of our understanding of the acoustical environments in hospitals. We focus on how proper acoustics can increase the quality of patient care and improve the healing environment.
Over the past two years we have been fortunate to have the opportunity to work with Northwestern Memorial Hospital in Chicago to assess noise levels in the NICU, first in their former facility and more recently in their new facility that replaced it. In cooperation with NMH and BSA LifeStructures, our team not only studied noise levels in the former and new facility, but also compared light levels and assessed visitor and medical staff satisfaction. There have been studies performed at other hospitals, but to my knowledge, few if any have collected the detail of information that our team has collected and analyzed in these two facilities. Our monitoring took place during extended periods of time, during which team members logged minute by minute observations of activities in the NICU – observations that could later be correlated with the minute by minute log of the sound levels. Initial results of the family and staff surveys, the sound levels and their correlation to NICU activity, and the light levels have been presented to NMH. In the coming months we will be presenting the results to a broader audience at the Hospital and authoring papers to make our findings available to the medical community and to the healthcare facilities design community. Once these papers are published, I will be sure to post a notice in the Acoustics By Design, Inc., blog so that those of you that are interested can read the details of the study and our team’s findings.